All 250,000 street lights in the city are going to be replaced with energy-efficient LEDs by 2017, Mayor Bloomberg is announcing Thursday.

The mayor has scheduled a press conference with Transportation Commissioner Janette Sadik-Khan on Eastern Parkway in Brooklyn to unveil the details.

The city began testing LEDs on street fixtures in 2009, when 13 were installed in Central Park from East 67th to East 72d Streets and another 24 were added along the FDR Drive’s center median between 18th and 24th Streets,

The timing of the installation aligns with the city’s goal of reducing municipal government gashouse emissions 30 percent by 2017.

It’ll be up to the next mayor to meet that goal, since Bloomberg is leaving office on Dec. 31.